She was found dead Wednesday evening in her Tranquilla Avenue home after being shot at close range near the front door.

Atascadero police Chief Jerel Haley said Saturday that detectives obtained a confession from Andrews during an interview, but declined to comment further on the specifics of the conversation.

Haley said police are investigating a motive for the attack. There is no evidence to indicate that Barga-Milbury had a conflict with Andrews prior to the shooting.

A woman who answered the phone at Andrews’ home on Saturday declined to comment.

Police identified Andrews as a suspect thanks to an anonymous tip and “some good old-fashioned police work,” Haley said.

“Really, in about a 14-hour time span it came together,” Haley said.

Police received a tip Friday morning from someone “who was concerned and had a general feeling that this may be the suspect,” he said.

After Andrews became the focus of the police investigation, detectives started surveillance of his residence. Andrews was detained after leaving his home.

“Initially he was only detained and questioned by detectives,” Haley said. “There was enough evidence gathered to get a search warrant and go to his residence.”

There, police found a rifle consistent with the type of weapon that was believed to have been used in the shooting, but further tests are needed for confirmation.

Detectives also found a hand grenade — which contained live primer but no powder. The county Sheriff’s Office bomb task force was briefly called to the scene to dispose of it. It’s unknown if the grenade belonged to Andrews or someone else in the home, Haley said.

“It was technically considered live, but not the kind that would do a significant amount of damage if it went off,” he added. “We don’t think it was intended for any use that we know about.”

Atascadero police also seized numerous other firearms, including handguns and rifles, from Andrews’ home. It was unknown whether any of the firearms were registered to Andrews.

Police said Andrews has mental health issues and detectives are investigating whether that may have been a contributing factor in the alleged murder.

Atascadero police and Paso Robles police volunteers have been conducting extra patrols of the area since the shooting happened. With Andrews’ arrest, the patrols will stop.